U.S. patent number 7,206,672 [Application Number 10/962,776] was granted by the patent office on 2007-04-17 for vehicle data bus system.
This patent grant is currently assigned to DaimlerChrysler AG. Invention is credited to Achim Mueller.
United States Patent |
7,206,672 |
Mueller |
April 17, 2007 |
Vehicle data bus system
Abstract
The invention concerns a data bus system (30) including a
communication unit (40) for bidirectional wireless communication
with at least one unit (20) outside of the vehicle (10) and with
vehicle units (50, 60, 70, 72, 74, 76, 78, 80, 90, 110, 120, 130,
140) which are in data transmission communication with the
communication unit (40) via at least one data bus (150, 152, 154),
wherein data as to status of the vehicle units (50, 60, 70, 72, 74,
76, 78, 80, 90, 110, 120, 130, 140) is transmitted via the at least
one data bus (150, 152, 154) to the communication unit (40) and
transmittable via the communication unit (40) to at least one unit
(20) outside the vehicle. According to the invention, a triggering
event (E) is received by the vehicle units (50, 60, 70, 72, 74, 76,
78, 80, 90, 110, 120, 130, 140) via at least one data bus (150,
152, 154), and the vehicle units (50, 60, 70, 72, 74, 76, 78, 80,
90, 110, 120, 130, 140) upon receipt of the triggered event (E)
transmit their status data via the at least one data bus (150, 152,
154) to the communication unit (40).
Inventors: |
Mueller; Achim (Gerlingen,
DE) |
Assignee: |
DaimlerChrysler AG (Stuttgart,
DE)
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Family
ID: |
33441832 |
Appl.
No.: |
10/962,776 |
Filed: |
October 12, 2004 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050102069 A1 |
May 12, 2005 |
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Foreign Application Priority Data
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Oct 10, 2003 [DE] |
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103 47 836 |
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Current U.S.
Class: |
701/1; 340/989;
455/420 |
Current CPC
Class: |
G07C
5/008 (20130101) |
Current International
Class: |
H04Q
7/20 (20060101); F02D 45/00 (20060101) |
Field of
Search: |
;701/1,213
;340/989,988,825.49 ;342/357.07,357.09,457
;455/420,3.01,3.03,346,574 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tran; Dalena
Attorney, Agent or Firm: Akerman & Senterfitt Pendorf;
Stephen A. Chen; Yonghong
Claims
The invention claimed is:
1. A vehicle data bus system (30), comprising: a communication unit
(40) for bidirectional wireless communication with at least one
unit (20) outside of the vehicle (10) and with vehicle units (50,
60, 70, 72, 74, 76, 78, 80, 90, 110, 220, 130, 140) which are in
data transmission communication with the communication unit (40)
via at least one data bus (150, 152, 154), wherein data as to
status of the vehicle units (50, 60, 70, 72, 74, 76, 78, 80, 90,
110, 120, 130, 140) is transmitted via the at least one data bus
(150, 152, 154) to the communication unit (40) and transmittable
via the communication unit (40) to the at least one unit (20)
outside the vehicle, wherein communication between the
communication unit (40) and the at least one unit (20) outside the
vehicle is enabled following occurrence of a triggering event (E)
and prior to expiration of a first predetermined time interval (T1)
and an inactive operating mode in which the communication unit is
switched off is initiated following conclusion of the first
predetermined time interval (T1), wherein a second operating mode
is assumed by the vehicle units (50, 60, 70, 72, 74, 76, 78, 80,
90, 110, 120, 130, 140) following the occurrence of the triggering
event (E) and alter expiration of a second predetermined time
interval (T2) where energy consumption is reduced in comparison to
a normal operating mode, wherein the triggering event (E) is
received by the vehicle units (50, 60, 70, 72, 74, 76, 78, 80, 90,
110, 120, 130, 140) via the at least one data bus (150, 152, 154),
wherein the vehicle units (50, 60, 70, 72, 74, 76, 78, 80, 90, 110,
120, 130, 140) upon receipt of the triggering event (E) transmit
their status data via the at least one data bus (150, 152, 154) to
the communication unit (40) for storage therein during the second
predetermined time interval (T2), and wherein the first
predetermined time interval (T1) is longer than the second
predetermined time interval (T2), during the time period after the
conclusion of the second predetermined time interval (T2) and
before the completion of the first predetermined time interval
(T1), the communication unit (40) answers interrogation about the
status of the vehicle units (50, 60, 70, 72, 74, 76, 78, 80, 90,
110, 120, 130, 140) on the basis of the status data received via
the data bus (30) and stored in the communication unit (40).
2. The vehicle data bus system according to claim 1 wherein the
triggering event (E) is received by the communication device (40)
via the at least one data bus (150, 152, 154).
3. The vehicle data bus system according to claim 1, wherein the
triggering event (E) includes an "ignition off" event, which is
transmitted as a signal via the at least one data bus (150, 152,
154).
4. The vehicle data bus system according to claim 1, wherein prior
to expiration of the predetermined time interval (T1) the status
data stored in the communication unit (40) is transmittable to the
at least one unit (20) outside of the vehicle (10) via the
communication unit (40).
5. The vehicle data bus system according to claim 1, wherein the
communication unit (40) is adapted to being switched, by a wakeup
signal received via the data bus, from a deactivated operating mode
to a mode in which communication via the communication unit (40) is
possible.
6. The vehicle data bus system according to claim 1, wherein the
vehicle units (50, 60, 70, 72, 74, 76, 78, 80, 90, 110, 120, 130,
140) are switchable, via a wakeup signal received via the at least
one data bus (150, 152, 154), from the second operating mode into
their normal operating mode.
7. The vehicle data bus system according to claim 6, wherein the
wakeup signal is received by the communication signal (40) dining
the first predetermined time interval (T1).
8. The vehicle data bus system according to claim 1, wherein the
second predetermined time interval (T2) is significantly less than
the first predetermined time interval (T1).
9. The vehicle data bus system according to claim 1, wherein stored
data in the communication unit (40) for the vehicle units (50, 60,
70, 72, 74, 76, 78, 80, 90, 110, 120, 130, 140) are only accessible
to the at least one unit (20) outside of the vehicle (10) via the
communication unit (40) after the second predetermined time
interval (T2) and during the first predetermined time interval
(T1).
10. The vehicle data bus system according to claim 1, wherein the
vehicle data bus system provides battery savings by preventing
communication between the communication unit (40) and the at least
one unit (20) outside of the vehicle (10) during a time frame
outside of the predetermined time interval (T1) during the inactive
operating mode and provides further battery savings by preventing
communication between the communication unit (40) and the vehicle
units (50, 60, 70, 72, 74, 76, 78, 80, 90, 110) 120, 130, 140)
during a time frame outside of the second predetermined time
interval (T2) during the second operating mode.
11. The vehicle data bus system according to claim 10, wherein the
communication unit (40) and the vehicle units (50, 60, 70, 72, 74,
76, 78, 80, 90, 110, 120, 130, 140) communicate when the second
operating mode is disabled.
12. The vehicle data bus system according to claim 10, wherein the
communication unit (40) refrains from communicating with the
vehicle units (50, 60, 70, 72, 74, 76, 78, 80, 90, 110, 120, 130,
140) during the first predetermined time interval (T1) and
transmits status data of the vehicle units (50, 60, 70, 72, 74, 76,
78, 80, 90, 110, 120, 130, 140) stored in the communication unit
(40) to the at least one unit (20) when the at least one unit (20)
outside of the vehicle (10) makes an inquiry of the communication
unit (40).
Description
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention concerns a vehicle data bus system of the type set
forth in the precharacterizing portion of Patent Claim 1.
2. Related Art of the Invention
U.S. Pat. No. 6,028,537 describes a vehicle data bus system wherein
signals for control of functions of vehicle devices are receivable
from a center via a communication device.
SUMMARY OF THE INVENTION
It is the task of the invention to provide an improved vehicle data
bus system, via which the energy supply in the vehicle battery can
be better utilized.
The invention solves this task by providing a vehicle data bus
system having the characteristics of Patent Claim 1.
Advantageous further developments of the invention are set forth in
the dependent claims.
It is the basic idea of the invention, that status data is
transmitted from bus-networked vehicle devices to the communication
device of the vehicle after parking of the vehicle. This concerns
in particular all vehicle devices for which status data can be
interrogated from outside the vehicle via the communication
device.
In a preferred embodiment of the invention the communication device
is switched to an inactive mode after a certain period of time
following parking of the vehicle, wherein it is no longer available
for communication. There is also a (concurrent) second
predetermined time interval, after the expiration of which the
vehicle devices are switched to a so-called "sleep-mode", in which
the energy requirement of the vehicle devices is reduced in
comparison to the normal mode. Preferably, the predetermined time
interval is longer than the second predetermined time interval. In
the time following conclusion of the second predetermined time
interval and prior to completion of the predetermined time interval
the communication device is available for communication, the
vehicle devices are however already in the "sleep-mode". In this
condition it is particularly advantageous, that the status data of
all vehicle devices, of which the status data can be interrogated
from outside the vehicle via the communication device, is in memory
in the communication device. In the case of an interrogation as to
status data (data retrieval) from outside, that is, via the
communication device, the communication device can answer the
interrogation directly on the basis of the stored status data. No
activation of the vehicle bus data system is necessary. This
preserves the reserve of energy in the vehicle battery and has the
consequence that the vehicle in the parked condition has
starting-up energy available for a longer period of time.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be now described in greater detail on the basis
of the illustrated examples shown in the figures. There is
shown:
FIG. 1 a schematic representation of the vehicle data bus
system,
FIG. 2 a schematic representation of a vehicle with a communication
link to a unit outside of the vehicle,
FIG. 3 a schematic representation of the time sequence illustrating
energy management,
FIG. 4 a schematic representation of the data exchange
relationship, using the example of an independent vehicle
heater,
FIG. 5 a schematic representation of the data exchange
relationship, using the example of a vehicle locking function.
Corresponding parts in all figures are provided with the same
reference numbers.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a schematic representation of a vehicle data bus
system 30 with a communication unit 40. The vehicle data bus system
30 shown in FIG. 1 includes a gateway 50, a "keyless go" unit 60,
door control devices 70, 72, 74, 76, a signal acquisition and
control module 78, an ignition switch control device 80, a roof
operating unit 90, a independent vehicle heater 100, a seat heater
110, an energy control device 120, a display and operation unit
130, an instrument cluster (instrument control device) 140 and data
buses 150, 152, 154. The data bus 150 is for example a CAN class D
bus. The data bus 152 is for example a so-called "backbone", that
is, a data bus with very high data transmission rate. The data bus
154 is for example a CAN class B bus or CAN class C bus. The
gateway 50 enables data transmission between the various data buses
150, 152, 154. The units 40, 50, 60, 70, 72, 74, 76, 78, 80, 90,
110, 120, 130, 140 can individually also be connected via discrete
lines or circuits and/or be wireless linked. Also conceivable are
mixtures of the topologies, discrete connections and/or data buses.
It is likewise conceivable to incorporate various units in a single
housing. One or more of the data buses can be in the form of, for
example, a ring shaped bus, in particular an optical bus such as,
for example, D2B (Domestic Digital Bus) or MOST (Media Oriented
Systems Transport).
The communication device 40 receives inquires regarding status data
from the unit 20, for example the center, via the communication
device 25. These interrogations of status data are answered by the
vehicle 10 using the actual status data of the vehicle units 50,
60, 70, 72, 74, 76, 78, 80, 90, 110, 120, 130, 140, in that the
inquired about status data are transmitted via the communication
device 40 to the unit 20.
Besides this, in the vehicle units 50, 60, 70, 72, 74, 76, 78, 80,
90, 110, 120, 130, 140 a number of vehicle functions are
controllable via control signals which are received by the
communication device 40 from the unit 20, for example, a
geographically fixed center. The control signals are transmitted
via one or more data buses to the relevant units to be controlled
and these carry out the desired actions.
The functions in the vehicle devices 50, 60, 70, 72, 74, 76, 78,
80, 90, 110, 120, 130, 140 include, for example, the locking
function for locking of vehicle doors, as well as the trunk lid and
the gas fill lid, an independent vehicle heater, as well as air
conditioning (climate control), functions for opening and closing
windows and the retractable roof, seat heaters, etc. Functions to
be carried include for example the opening or closing of windows,
the locking of the vehicle, the activation or deactivation of the
vehicle independent heater, the deicing of the windshields and/or
the ventilation of the vehicle, etc. Besides this, functions to be
carried out include the programming of individual functions, for
example, programming of a time for activation of the independent
vehicle heater, etc.
FIG. 2 schematically shows the communication relationship
established between a unit 20 and, as an example, a geographically
fixed center.
A user obtains access to the computer system of the geographically
fixed center 20, for example via the internet 210 using his home
computer 240. Alternatively, or additionally, the user can gain
access to the unit 20 via a mobile telephone 260 through a mobile
internet, for example WAP (Wireless Application Protocol).
Following authentication by the unit 20 the user is associated or
connected with a specific vehicle 10. Via the internet 210 and/or
the mobile internet 230 the user can, following authentication,
transmit interrogatories for status of vehicle functions to the
unit 20. The unit 20 transmits the request for status data via the
communication unit 25 to the vehicle 10. The vehicle 10 receives
the status inquiry via the communication unit 40. In response, the
communication device 40 transmits the requested status data to the
unit 20.
In a preferred embodiment of the invention the user can transmit,
following authentication, supplemental control instructions to the
unit 20 via the internet 210 and/or the mobile internet 230 for
remote control of vehicle functions. The unit 20 transmits the
control instructions or commands via the communication unit 25 to
the vehicle 10. The vehicle 10 receives the control instructions
via the communication unit 40. In a preferred embodiment of the
invention, after receipt of the control signals in the vehicle 10
it is checked whether the energy stored in the vehicle battery is
sufficient to carry out the requested functions. If sufficient
energy remains available in the battery, then the function is
carried out and the appropriate response is transmitted via the
communication device 40 to the unit 20. If it is determined in the
vehicle 10 that the energy reserve in the battery is not sufficient
to carry out the requested function and/or the energy reserve
following the carrying out of the requested function would lie
below a predetermined threshold, then the function is not carried
out and an appropriate reply is transmitted via the communication
unit 40 to the unit 20.
In FIG. 3 a time sequence showing energy management is
schematically represented. Following event E "ignition off" the
vehicle units 50, 60, 70, 72, 74, 76, 78, 80, 90, 110, 120, 130,
140 transmit their status data to the communication device 40. The
communication device 40 then stores the status data received from
the vehicle units 50, 60, 70, 72, 74, 76, 78, 80, 90, 110, 120,
130, 140.
As shown in FIG. 3, for a period of time T1 following the event E
"ignition off" a follow-up mode for the communication unit 40 is
provided. In the follow-up mode the communication unit 40 continues
to remain communication-ready. This means for example that the
communication unit 40 continues to remain logged in to a cellular
mobile radio network. Following conclusion of time interval T1 the
communication unit 40 switches itself off. In the switched-off mode
the communication device 40 is no longer available for
communication, that is, it cannot establish a communication link
and it is not possible from outside, for example through unit 20
via communication unit 25, to establish a communication link with
the communication unit 40. A remote control of vehicle functions
and/or an interrogation of status data of the vehicle by unit 20 is
not possible in the switched-off mode of the communication device
40. The energy consumption of the communication device 40 in the
follow-up mode is higher than in the switched off mode. If the
communication unit 40 is kept continuously ready for communication,
then the energy supply in the battery would constantly be expended
and eventually the vehicle would not be able to start. This is
avoided in that, following conclusion of the time interval T1, the
communication unit 40 is deactivated and thereby its energy
consumption is minimized. Preferably the communication unit
receives the event E "ignition off" as a signal via the one or more
data buses 150, 152, 154.
In a preferred embodiment of the invention the vehicle units 50,
60, 70, 72, 74, 76, 78, 80, 90, 110, 120, 130, 140, following
conclusion of the time interval T2 after the event E "ignition
off", assume a so-called "sleep-mode". This mode is a mode of the
units 50, 60, 70, 72, 74, 76, 78, 80, 90, 110, 120, 130, 140, in
which energy consumption is reduced in comparison to normal
operation. It is also possible thereby to reduce the energy
consumption of the vehicle 10, so that the vehicle while parked
maintains readiness to start for longer periods of time. Preferably
the vehicle units 50, 60, 70, 72, 74, 76, 78, 80, 90, 110, 120,
130, 140 receive the event E "ignition off" as a signal via the one
or more data buses 150, 152, 154.
Preferably the vehicle units 50, 60, 70, 72, 74, 76, 78, 80, 90,
110, 120, 130, 140 go into the sleep-mode also after the carrying
out of a remote activated vehicle function. This occurs following a
third predetermined time interval T3 following the conclusion of
the carrying out of that function.
Preferably the transmission of the data regarding the status of the
vehicle units 50, 60, 70, 72, 74, 76, 78, 80, 90, 110, 120, 130,
140 occurs prior to the end of time interval T2 following event E.
This has the advantage that the receipt of a question regarding
status data following conclusion of the time interval T2, however
prior to conclusion of time interval T1 after event E, the status
data is directly available in the communication unit 40. The
communication unit 40 can thus directly answer a question regarding
status data, without having to "wakeup" the vehicle data bus system
30 in its entirety together with units 50, 60, 70, 72, 74, 76, 78,
80, 90, 110, 120, 130, 140. This likewise contributes thereto, that
the energy supply remaining in the vehicle battery remains
available longer in the parked condition of the vehicle 10.
Preferably the communication unit 40 and/or the units 50, 60, 70,
72, 74, 76, 78, 80, 90, 110, 120, 130, 140 can be awakened by a
wakeup signal via the one or more data buses 150, 152, 154.
Thereby, a waking up of the vehicle data bus system 30 can be
ensured, when for example the vehicle 10 is unlocked by a remote
control signal from the user and/or the door knob of a vehicle door
is operated.
Preferably the time interval T2 is substantially shorter than the
time interval T1. Thus, the communication readiness of the
communication unit 40 is ensured. This can, as required, for
example upon receipt of a control signal for a vehicle function,
wake up the units 50, 60, 70, 72, 74, 76, 78, 80, 90, 110, 120,
130, 140 via a wakeup signal via the one or more data buses.
In a further advantageous embodiment of the invention the unit 120
is connected directly with the communication unit 40, so that for a
status inquiry regarding the energy supply 124 the entire bus
system 3 need not be awakened.
FIG. 4 shows by way of example the sequence in the vehicle 10, with
the associated data exchange in the vehicle 10, in the case of the
remote control of a vehicle function, namely, vehicle independent
heating. FIG. 5 shows by way of example the sequence in the vehicle
10, with the associated data exchange in the vehicle 10, in the
case of the remote control of a vehicle function, namely, vehicle
locking. The data exchange shown schematically in FIG. 4 and FIG. 5
can occur via one or more busses and/or via discrete lines or
circuits. The communication between the unit 20 and the
communication unit 40 occurs via the communication unit 25, which
is not shown in FIG. 4 and FIG. 5.
The data 24, which is received by the communication unit 40 from
the unit 20, includes, in the example wherein the function is
vehicle independent heating as shown in FIG. 4, a starting signal
for starting the vehicle heater and a stop signal for stopping the
vehicle heater, a time signal for setting the starting time of the
vehicle independent heater and/or the signal for canceling the
start time. From the vehicle 10 the following status data 42
concerning the vehicle independent heater can be transmitted via
the communication unit 40 to the unit 20: status "ignition on",
status "remote control of vehicle independent heater deactivated",
status "energy supply insufficient", status "client programmed
temperature cannot be attained by the desired time" and/or status
"service activated". The data 413 transmitted from the
communication device 40 to the display and operating unit 130
includes the signals shown by way of example in FIG. 4, with which
the condition of the remote control of the independent heater
stored most recently in the communication device 40--"activated" or
"deactivated"--can be transmitted to the display and operating unit
130. The transmitted condition can be output or, as the case may
be, displayed in the display and operating unit 130. The data 134
transmitted from the display and operating unit 130 to the
communication unit 40 includes in the illustrated embodiment the
status indications, that the user has activated or deactivated the
service for remote control of the vehicle independent heater, on
the display and operating unit 130. The data 144 transmitted from
the instrument cluster 140, that is, the instrument control device,
to the communication device include in the illustrated embodiment a
signal reporting that the temperature desired by the client cannot
be achieved. This content or information can be determined for
example from the vehicle independent heater or the climate control
and be stored in the instrument cluster or instrument combination
140, from which the signal can then be transmitted to the
communication device 40. The data 410 transmitted from the
communication device 40 to the vehicle independent heater 100 can
include a signal for immediate activation of the vehicle
independent heater, a signal for immediate deactivation of the
vehicle independent heater, or a signal for programming a start
time for the vehicle independent heater, or a signal for canceling
the time for programming the start time for the vehicle heater. The
data 140 transmitted from the vehicle independent heater 100 to the
communication device 40 is optional and could include for example
status data regarding the vehicle independent heater.
If the communication unit 40 receives a signal from among the
possible signals of data 24 that concern the remote control of the
vehicle functions, that is, the received signal includes a signal
for control of vehicle functions, then the communication unit 40
transmits the inquiry 412 to the energy control device 120 in order
to determine the value 124 of the actual energy reserve in the
battery. This value 124 is transmitted from the energy control
device 120 to the communication device 40. In the example shown in
FIG. 4 the inquiry to the energy control device is carried out when
the signal 24 which concerns the vehicle independent heater is
received.
Using the value 124 the communication device 40 determines whether
the carrying out of the vehicle function--for example heating with
the vehicle independent heater--can be reconciled with the still
available energy reserve. If the energy supply in storage does not
suffice for carrying out the function or if upon carrying out the
function the residual energy supply would drop below a
predetermined threshold, then the communication unit makes the
decision not to carryout the function. The unit 20 is, beyond this,
informed by a status signal "energy supply insufficient" of data
42. If the stored energy supply is sufficient for carrying out the
function and/or if upon carrying out the function the residual
energy supply would not drop below a predetermined threshold, then
the communication unit makes the decision to carry out the
function. The unit 20 is, beyond this, informed by the status
signal "service activated" of data 42.
The data 24, which are received by the communication unit 40 from
the unit 20, include, in the example of the vehicle locking
function of FIG. 5, a signal for locking the vehicle 10. From the
vehicle 10 the following status data 42 concerning the vehicle
locking and the unit 20 is transmitted via the communication device
40: status "ignition on", status "vehicle locking deactivated",
status "energy supply insufficient" and/or status "vehicle locked".
The data 413 transmitted from the communication unit 40 to the
display and operation unit 130 include, in the example shown in
FIG. 5, signals as to which condition of the remote control vehicle
unlocking device was most recently stored in the communication unit
40--"activated" or "deactivated". The transmitted condition can
then be output or, as the case may be, displayed in the display and
operation unit 130. The data 134 transmitted from the display and
operation unit 130 to the communication device 40 include in the
illustrated example the status messages that the user has activated
or deactivated the service for remote control vehicle unlocking.
These messages are transmitted to the communication device 40. The
data 414 is transmitted to the instrument cluster 140, that is, the
instrument control device, which in the shown example includes the
data 414 of the status signal that the vehicle is being operated
remotely. From the instrument cluster 140, that is, the instrument
control device, the data 144 are transmitted to the communication
unit, in the shown example the data 144 include the status signal
as to the status that the vehicle was unlocked remotely, and stored
in the combination instrument 140 so that it can as needed be
displayed. The data 48 transmitted from the communication unit 40
to the ignition lock control device 80 includes in the shown
example of the vehicle locking function a signal for locking the
vehicle. In the ignition lock device this signal is converted to
signals 870, 872, 874, 876, 878. Respectively one of the signals
870, 872, 874, 876, 878 is transmitted to one of the units 70, 72,
74, 76, 78, from which respectively the locking mechanisms for the
doors, the trunk lid as well as the gas tank lock, etc. are
controlled. The signals 708, 728, 748, 768 and 788 are optional and
can include status data of the units 70, 72, 74, 76, 78. The data
84 transmitted from the ignition lock control device 80 to the
communication unit 40 is optional and can include for example
status data regarding the ignition lock device.
If the communication device 40 receives a signal from among the
possible signals of data 24 that concern vehicle locking, that is,
a signal for control of vehicle functions, then the communication
unit 40 sends an inquiry 412 to the energy control device 120, in
order to determine the value 124 of the actual battery reserve or
energy supply in the battery. This value 124 is transmitted from
the energy control device 120 to the communication unit 40. In the
example shown in FIG. 5 the inquiry to the energy control device is
carried out when the signal 24 concerning vehicle locking is
received.
Using the value 124 it is determined in the communication device 40
whether the carrying out of the vehicle function--in this example
vehicle locking--is reconcilable with the remaining energy supply.
If the energy supply in storage is not sufficient for carrying out
the function, or if the carrying out of the function would cause
the remaining energy supply to drop below a predetermined
threshold, then the communication unit arrives at the decision not
to carry out the function. The unit 20 is, beyond this, informed of
the data 42 by a status signal "energy supply insufficient". If the
remaining energy supply is sufficient for carrying out the function
and/or if the carrying out of the function does not cause the
residual energy supply to drop below a predetermined threshold,
then the communication unit arrives at the decision to carry out
the function. The unit 20 is, beyond this, informed of the data 42
by a status signal "vehicle locked".
* * * * *